Treatment of exhaust gases and fumes

If we take a global approach, the impact on human health and ecosystems, the greenhouse effect and global warming, the uncontrolled production of ozone in city centers, odor nuisance... are all good reasons to drastically limit the pollutants present in gaseous emissions and smoke. These include particulates, sulfur compounds, nitrogen compounds, carbon dioxide, metals and volatile organic compounds. The international community has mobilized to combat the increase in anthropogenic greenhouse gas emissions through the Convention signed in Rio de Janeiro in June 1992. Since then, international conferences have been held, with varying degrees of success, in Kyoto and New York, focusing in particular on the issue of air pollution. The annual Conferences of the Parties, including COP21 (21st Conference of the Parties) held in Paris in 2015 and COP28 in Dubai in 2023, have enabled discussion and definition of objectives between States on the management of gaseous emissions. These agreements should lead to a drastic reduction in certain pollutants present in emissions caused by human activity. On the regulatory front, the ratification of these international treaties has led to the practical consequences of European directives such as 2008/50/CE (CAFE directive for Clean Air For Europe). In particular, they regulate pollutant emission levels for installations classified for environmental protection (ICPE) and for certain industrial sectors. These include the decree of February 2, 1998, supplemented by decrees amending the decree for specific industries. These few points are intended to demonstrate the need and/or obligation to reduce the pollutant load emitted into the atmosphere by fumes. There are a number of processes that can help reduce these pollutant emissions and nuisances.

The aim of this article is to define qualitatively and quantitatively the pollutants emitted in flue gases, to introduce the regulatory texts in the field of pollution control, and to present methods for analyzing various undesirable compounds. Lastly, it will present the treatments available for flue gas purification, either on their own or as part of a process.